/// \brief Find an insertion point that dominates all uses.
Instruction *ConstantHoisting::
findConstantInsertionPoint(const ConstantInfo &ConstInfo) const {
assert(!ConstInfo.RebasedConstants.empty() && "Invalid constant info entry.");
// Collect all IDoms.
SmallPtrSet<BasicBlock *, 8> BBs;
for (auto const &RCI : ConstInfo.RebasedConstants)
BBs.insert(getIDom(RCI));
assert(!BBs.empty() && "No dominators!?");
if (BBs.count(Entry))
return &Entry->front();
while (BBs.size() >= 2) {
BasicBlock *BB, *BB1, *BB2;
BB1 = *BBs.begin();
BB2 = *std::next(BBs.begin());
BB = DT->findNearestCommonDominator(BB1, BB2);
if (BB == Entry)
return &Entry->front();
BBs.erase(BB1);
BBs.erase(BB2);
BBs.insert(BB);
}
assert((BBs.size() == 1) && "Expected only one element.");
Instruction &FirstInst = (*BBs.begin())->front();
return findMatInsertPt(&FirstInst);
}
bool UnreachableBlockElim::runOnFunction(Function &F) {
SmallPtrSet<BasicBlock*, 8> Reachable;
// Mark all reachable blocks.
for (df_ext_iterator<Function*, SmallPtrSet<BasicBlock*, 8> > I =
df_ext_begin(&F, Reachable), E = df_ext_end(&F, Reachable); I != E; ++I)
/* Mark all reachable blocks */;
// Loop over all dead blocks, remembering them and deleting all instructions
// in them.
std::vector<BasicBlock*> DeadBlocks;
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
if (!Reachable.count(I)) {
BasicBlock *BB = I;
DeadBlocks.push_back(BB);
while (PHINode *PN = dyn_cast<PHINode>(BB->begin())) {
PN->replaceAllUsesWith(Constant::getNullValue(PN->getType()));
BB->getInstList().pop_front();
}
for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
(*SI)->removePredecessor(BB);
BB->dropAllReferences();
}
// Actually remove the blocks now.
ProfileInfo *PI = getAnalysisIfAvailable<ProfileInfo>();
for (unsigned i = 0, e = DeadBlocks.size(); i != e; ++i) {
if (PI) PI->removeBlock(DeadBlocks[i]);
DeadBlocks[i]->eraseFromParent();
}
return DeadBlocks.size();
}
// Check PHI instructions at the beginning of MBB. It is assumed that
// calcRegsPassed has been run so BBInfo::isLiveOut is valid.
void MachineVerifier::checkPHIOps(const MachineBasicBlock *MBB) {
SmallPtrSet<const MachineBasicBlock*, 8> seen;
for (MachineBasicBlock::const_iterator BBI = MBB->begin(), BBE = MBB->end();
BBI != BBE && BBI->isPHI(); ++BBI) {
seen.clear();
for (unsigned i = 1, e = BBI->getNumOperands(); i != e; i += 2) {
unsigned Reg = BBI->getOperand(i).getReg();
const MachineBasicBlock *Pre = BBI->getOperand(i + 1).getMBB();
if (!Pre->isSuccessor(MBB))
continue;
seen.insert(Pre);
BBInfo &PrInfo = MBBInfoMap[Pre];
if (PrInfo.reachable && !PrInfo.isLiveOut(Reg))
report("PHI operand is not live-out from predecessor",
&BBI->getOperand(i), i);
}
// Did we see all predecessors?
for (MachineBasicBlock::const_pred_iterator PrI = MBB->pred_begin(),
PrE = MBB->pred_end(); PrI != PrE; ++PrI) {
if (!seen.count(*PrI)) {
report("Missing PHI operand", BBI);
*OS << "BB#" << (*PrI)->getNumber()
<< " is a predecessor according to the CFG.\n";
}
}
}
}
static void EliminateMultipleEntryLoops(MachineFunction &MF,
const MachineLoopInfo &MLI) {
SmallPtrSet<MachineBasicBlock *, 8> InSet;
for (scc_iterator<MachineFunction *> I = scc_begin(&MF), E = scc_end(&MF);
I != E; ++I) {
const std::vector<MachineBasicBlock *> &CurrentSCC = *I;
// Skip trivial SCCs.
if (CurrentSCC.size() == 1)
continue;
InSet.insert(CurrentSCC.begin(), CurrentSCC.end());
MachineBasicBlock *Header = nullptr;
for (MachineBasicBlock *MBB : CurrentSCC) {
for (MachineBasicBlock *Pred : MBB->predecessors()) {
if (InSet.count(Pred))
continue;
if (!Header) {
Header = MBB;
break;
}
// TODO: Implement multiple-entry loops.
report_fatal_error("multiple-entry loops are not supported yet");
}
}
assert(MLI.isLoopHeader(Header));
InSet.clear();
}
}
/// isLiveInButUnusedBefore - Return true if register is livein the MBB not
/// not used before it reaches the MI that defines register.
static bool isLiveInButUnusedBefore(unsigned Reg, MachineInstr *MI,
MachineBasicBlock *MBB,
const TargetRegisterInfo *TRI,
MachineRegisterInfo* MRI) {
// First check if register is livein.
bool isLiveIn = false;
for (MachineBasicBlock::const_livein_iterator I = MBB->livein_begin(),
E = MBB->livein_end(); I != E; ++I)
if (Reg == *I || TRI->isSuperRegister(Reg, *I)) {
isLiveIn = true;
break;
}
if (!isLiveIn)
return false;
// Is there any use of it before the specified MI?
SmallPtrSet<MachineInstr*, 4> UsesInMBB;
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(Reg),
UE = MRI->use_end(); UI != UE; ++UI) {
MachineOperand &UseMO = UI.getOperand();
if (UseMO.isReg() && UseMO.isUndef())
continue;
MachineInstr *UseMI = &*UI;
if (UseMI->getParent() == MBB)
UsesInMBB.insert(UseMI);
}
if (UsesInMBB.empty())
return true;
for (MachineBasicBlock::iterator I = MBB->begin(), E = MI; I != E; ++I)
if (UsesInMBB.count(&*I))
return false;
return true;
}
/// Collect cast instructions that can be ignored in the vectorizer's cost
/// model, given a reduction exit value and the minimal type in which the
/// reduction can be represented.
static void collectCastsToIgnore(Loop *TheLoop, Instruction *Exit,
Type *RecurrenceType,
SmallPtrSetImpl<Instruction *> &Casts) {
SmallVector<Instruction *, 8> Worklist;
SmallPtrSet<Instruction *, 8> Visited;
Worklist.push_back(Exit);
while (!Worklist.empty()) {
Instruction *Val = Worklist.pop_back_val();
Visited.insert(Val);
if (auto *Cast = dyn_cast<CastInst>(Val))
if (Cast->getSrcTy() == RecurrenceType) {
// If the source type of a cast instruction is equal to the recurrence
// type, it will be eliminated, and should be ignored in the vectorizer
// cost model.
Casts.insert(Cast);
continue;
}
// Add all operands to the work list if they are loop-varying values that
// we haven't yet visited.
for (Value *O : cast<User>(Val)->operands())
if (auto *I = dyn_cast<Instruction>(O))
if (TheLoop->contains(I) && !Visited.count(I))
Worklist.push_back(I);
}
}
bool LowerIntrinsics::InsertRootInitializers(Function &F, AllocaInst **Roots,
unsigned Count) {
// Scroll past alloca instructions.
BasicBlock::iterator IP = F.getEntryBlock().begin();
while (isa<AllocaInst>(IP)) ++IP;
// Search for initializers in the initial BB.
SmallPtrSet<AllocaInst*,16> InitedRoots;
for (; !CouldBecomeSafePoint(IP); ++IP)
if (StoreInst *SI = dyn_cast<StoreInst>(IP))
if (AllocaInst *AI =
dyn_cast<AllocaInst>(SI->getOperand(1)->stripPointerCasts()))
InitedRoots.insert(AI);
// Add root initializers.
bool MadeChange = false;
for (AllocaInst **I = Roots, **E = Roots + Count; I != E; ++I)
if (!InitedRoots.count(*I)) {
StoreInst* SI = new StoreInst(ConstantPointerNull::get(cast<PointerType>(
cast<PointerType>((*I)->getType())->getElementType())),
*I);
SI->insertAfter(*I);
MadeChange = true;
}
return MadeChange;
}
bool LowerIntrinsics::InsertRootInitializers(Function &F, Instruction **Roots,
unsigned Count) {
// Scroll past alloca instructions.
BasicBlock::iterator IP = F.getEntryBlock().begin();
while (isa<AllocaInst>(IP)) ++IP;
// Search for initializers in the initial BB.
SmallPtrSet<AllocaInst*,16> InitedRoots;
for (; !CouldBecomeSafePoint(IP); ++IP)
if (StoreInst *SI = dyn_cast<StoreInst>(IP))
if (AllocaInst *AI =
dyn_cast<AllocaInst>(SI->getOperand(1)->stripPointerCasts()))
InitedRoots.insert(AI);
// Add root initializers.
bool MadeChange = false;
for (Instruction **II = Roots, **IE = Roots + Count; II != IE; ++II) {
// Trace back through GEPs to find the actual alloca.
Instruction *I = *II;
while (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I))
I = cast<Instruction>(GEP->getPointerOperand());
AllocaInst *AI = cast<AllocaInst>(I);
if (!InitedRoots.count(AI)) {
Type *ElemTy = cast<PointerType>((*II)->getType())->getElementType();
PointerType *PElemTy = cast<PointerType>(ElemTy);
StoreInst* SI = new StoreInst(ConstantPointerNull::get(PElemTy), *II);
SI->insertAfter(*II);
MadeChange = true;
}
}
return MadeChange;
}
/// \brief Checks if the padding bytes of an argument could be accessed.
bool ArgPromotion::canPaddingBeAccessed(Argument *arg) {
assert(arg->hasByValAttr());
// Track all the pointers to the argument to make sure they are not captured.
SmallPtrSet<Value *, 16> PtrValues;
PtrValues.insert(arg);
// Track all of the stores.
SmallVector<StoreInst *, 16> Stores;
// Scan through the uses recursively to make sure the pointer is always used
// sanely.
SmallVector<Value *, 16> WorkList;
WorkList.insert(WorkList.end(), arg->user_begin(), arg->user_end());
while (!WorkList.empty()) {
Value *V = WorkList.back();
WorkList.pop_back();
if (isa<GetElementPtrInst>(V) || isa<PHINode>(V)) {
if (PtrValues.insert(V).second)
WorkList.insert(WorkList.end(), V->user_begin(), V->user_end());
} else if (StoreInst *Store = dyn_cast<StoreInst>(V)) {
Stores.push_back(Store);
} else if (!isa<LoadInst>(V)) {
return true;
}
}
// Check to make sure the pointers aren't captured
for (StoreInst *Store : Stores)
if (PtrValues.count(Store->getValueOperand()))
return true;
return false;
}
bool CfgNaive::runOnFunction(Function &F) {
errs() << F.getName() << "\n";
SmallPtrSet<BasicBlock*, 8> visitedBlocks;
// Mark all reachable blocks.
for (df_ext_iterator<Function*, SmallPtrSet<BasicBlock*, 8>> currentBlock = df_ext_begin(&F, visitedBlocks),
endBlock = df_ext_end(&F, visitedBlocks);
currentBlock != endBlock;
currentBlock++) {
//do nothing, iterator marks visited nodes automatically
}
// Build set of unreachable blocks
std::vector<BasicBlock*> unreachableBlocks;
for (Function::iterator currentBlock = F.begin(), endBlock = F.end(); currentBlock != endBlock; currentBlock++) {
if (visitedBlocks.count(currentBlock) == 0) {
unreachableBlocks.push_back(currentBlock);
}
}
// Remove unreachable blocks
for (int i = 0, e = unreachableBlocks.size(); i != e; i++) {
errs() << unreachableBlocks[i]->getName() << " is unreachable\n";
unreachableBlocks[i]->eraseFromParent();
}
bool hasModifiedBlocks = (unreachableBlocks.size() > 0);
return hasModifiedBlocks;
}
static bool bothUsedInPHI(const MachineBasicBlock &A,
const SmallPtrSet<MachineBasicBlock *, 8> &SuccsB) {
for (MachineBasicBlock *BB : A.successors())
if (SuccsB.count(BB) && !BB->empty() && BB->begin()->isPHI())
return true;
return false;
}
bool LiveVariables::runOnMachineFunction(MachineFunction &mf) {
MF = &mf;
MRI = &mf.getRegInfo();
TRI = MF->getSubtarget().getRegisterInfo();
const unsigned NumRegs = TRI->getNumRegs();
PhysRegDef.assign(NumRegs, nullptr);
PhysRegUse.assign(NumRegs, nullptr);
PHIVarInfo.resize(MF->getNumBlockIDs());
PHIJoins.clear();
// FIXME: LiveIntervals will be updated to remove its dependence on
// LiveVariables to improve compilation time and eliminate bizarre pass
// dependencies. Until then, we can't change much in -O0.
if (!MRI->isSSA())
report_fatal_error("regalloc=... not currently supported with -O0");
analyzePHINodes(mf);
// Calculate live variable information in depth first order on the CFG of the
// function. This guarantees that we will see the definition of a virtual
// register before its uses due to dominance properties of SSA (except for PHI
// nodes, which are treated as a special case).
MachineBasicBlock *Entry = &MF->front();
SmallPtrSet<MachineBasicBlock*,16> Visited;
for (MachineBasicBlock *MBB : depth_first_ext(Entry, Visited)) {
runOnBlock(MBB, NumRegs);
PhysRegDef.assign(NumRegs, nullptr);
PhysRegUse.assign(NumRegs, nullptr);
}
// Convert and transfer the dead / killed information we have gathered into
// VirtRegInfo onto MI's.
for (unsigned i = 0, e1 = VirtRegInfo.size(); i != e1; ++i) {
const unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
for (unsigned j = 0, e2 = VirtRegInfo[Reg].Kills.size(); j != e2; ++j)
if (VirtRegInfo[Reg].Kills[j] == MRI->getVRegDef(Reg))
VirtRegInfo[Reg].Kills[j]->addRegisterDead(Reg, TRI);
else
VirtRegInfo[Reg].Kills[j]->addRegisterKilled(Reg, TRI);
}
// Check to make sure there are no unreachable blocks in the MC CFG for the
// function. If so, it is due to a bug in the instruction selector or some
// other part of the code generator if this happens.
#ifndef NDEBUG
for(MachineFunction::iterator i = MF->begin(), e = MF->end(); i != e; ++i)
assert(Visited.count(&*i) != 0 && "unreachable basic block found");
#endif
PhysRegDef.clear();
PhysRegUse.clear();
PHIVarInfo.clear();
return false;
}
/// isProfitableToCSE - Return true if it's profitable to eliminate MI with a
/// common expression that defines Reg.
bool MachineCSE::isProfitableToCSE(unsigned CSReg, unsigned Reg,
MachineInstr *CSMI, MachineInstr *MI) {
// FIXME: Heuristics that works around the lack the live range splitting.
// Heuristics #1: Don't CSE "cheap" computation if the def is not local or in
// an immediate predecessor. We don't want to increase register pressure and
// end up causing other computation to be spilled.
if (MI->getDesc().isAsCheapAsAMove()) {
MachineBasicBlock *CSBB = CSMI->getParent();
MachineBasicBlock *BB = MI->getParent();
if (CSBB != BB && !CSBB->isSuccessor(BB))
return false;
}
// Heuristics #2: If the expression doesn't not use a vr and the only use
// of the redundant computation are copies, do not cse.
bool HasVRegUse = false;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
if (MO.isReg() && MO.isUse() &&
TargetRegisterInfo::isVirtualRegister(MO.getReg())) {
HasVRegUse = true;
break;
}
}
if (!HasVRegUse) {
bool HasNonCopyUse = false;
for (MachineRegisterInfo::use_nodbg_iterator I = MRI->use_nodbg_begin(Reg),
E = MRI->use_nodbg_end(); I != E; ++I) {
MachineInstr *Use = &*I;
// Ignore copies.
if (!Use->isCopyLike()) {
HasNonCopyUse = true;
break;
}
}
if (!HasNonCopyUse)
return false;
}
// Heuristics #3: If the common subexpression is used by PHIs, do not reuse
// it unless the defined value is already used in the BB of the new use.
bool HasPHI = false;
SmallPtrSet<MachineBasicBlock*, 4> CSBBs;
for (MachineRegisterInfo::use_nodbg_iterator I = MRI->use_nodbg_begin(CSReg),
E = MRI->use_nodbg_end(); I != E; ++I) {
MachineInstr *Use = &*I;
HasPHI |= Use->isPHI();
CSBBs.insert(Use->getParent());
}
if (!HasPHI)
return true;
return CSBBs.count(MI->getParent());
}
/// DetermineInsertionPoint - At this point, we're committed to promoting the
/// alloca using IDF's, and the standard SSA construction algorithm. Determine
/// which blocks need phi nodes and see if we can optimize out some work by
/// avoiding insertion of dead phi nodes.
void PromoteMem2Reg::DetermineInsertionPoint(AllocaInst *AI, unsigned AllocaNum,
AllocaInfo &Info) {
// Unique the set of defining blocks for efficient lookup.
SmallPtrSet<BasicBlock*, 32> DefBlocks;
DefBlocks.insert(Info.DefiningBlocks.begin(), Info.DefiningBlocks.end());
// Determine which blocks the value is live in. These are blocks which lead
// to uses.
SmallPtrSet<BasicBlock*, 32> LiveInBlocks;
ComputeLiveInBlocks(AI, Info, DefBlocks, LiveInBlocks);
// Compute the locations where PhiNodes need to be inserted. Look at the
// dominance frontier of EACH basic-block we have a write in.
unsigned CurrentVersion = 0;
SmallPtrSet<PHINode*, 16> InsertedPHINodes;
std::vector<std::pair<unsigned, BasicBlock*> > DFBlocks;
while (!Info.DefiningBlocks.empty()) {
BasicBlock *BB = Info.DefiningBlocks.back();
Info.DefiningBlocks.pop_back();
// Look up the DF for this write, add it to defining blocks.
DominanceFrontier::const_iterator it = DF.find(BB);
if (it == DF.end()) continue;
const DominanceFrontier::DomSetType &S = it->second;
// In theory we don't need the indirection through the DFBlocks vector.
// In practice, the order of calling QueuePhiNode would depend on the
// (unspecified) ordering of basic blocks in the dominance frontier,
// which would give PHI nodes non-determinstic subscripts. Fix this by
// processing blocks in order of the occurance in the function.
for (DominanceFrontier::DomSetType::const_iterator P = S.begin(),
PE = S.end(); P != PE; ++P) {
// If the frontier block is not in the live-in set for the alloca, don't
// bother processing it.
if (!LiveInBlocks.count(*P))
continue;
DFBlocks.push_back(std::make_pair(BBNumbers[*P], *P));
}
// Sort by which the block ordering in the function.
if (DFBlocks.size() > 1)
std::sort(DFBlocks.begin(), DFBlocks.end());
for (unsigned i = 0, e = DFBlocks.size(); i != e; ++i) {
BasicBlock *BB = DFBlocks[i].second;
if (QueuePhiNode(BB, AllocaNum, CurrentVersion, InsertedPHINodes))
Info.DefiningBlocks.push_back(BB);
}
DFBlocks.clear();
}
}
/// Recursively traverse the conformance lists to determine sole conforming
/// class, struct or enum type.
NominalTypeDecl *
ProtocolConformanceAnalysis::findSoleConformingType(ProtocolDecl *Protocol) {
/// First check in the SoleConformingTypeCache.
auto SoleConformingTypeIt = SoleConformingTypeCache.find(Protocol);
if (SoleConformingTypeIt != SoleConformingTypeCache.end())
return SoleConformingTypeIt->second;
SmallVector<ProtocolDecl *, 8> PDWorkList;
SmallPtrSet<ProtocolDecl *, 8> VisitedPDs;
NominalTypeDecl *SoleConformingNTD = nullptr;
PDWorkList.push_back(Protocol);
while (!PDWorkList.empty()) {
auto *PD = PDWorkList.pop_back_val();
// Protocols must have internal or lower access.
if (PD->getEffectiveAccess() > AccessLevel::Internal) {
return nullptr;
}
VisitedPDs.insert(PD);
auto NTDList = getConformances(PD);
for (auto *ConformingNTD : NTDList) {
// Recurse on protocol types.
if (auto *Proto = dyn_cast<ProtocolDecl>(ConformingNTD)) {
// Ignore visited protocol decls.
if (!VisitedPDs.count(Proto))
PDWorkList.push_back(Proto);
} else { // Classes, Structs and Enums are added here.
// Bail if more than one conforming types were found.
if (SoleConformingNTD && ConformingNTD != SoleConformingNTD) {
return nullptr;
} else {
SoleConformingNTD = ConformingNTD;
}
}
}
}
// Bail if we did not find a sole conforming type.
if (!SoleConformingNTD)
return nullptr;
// Generic declarations are ignored.
if (SoleConformingNTD->isGenericContext()) {
return nullptr;
}
// Populate SoleConformingTypeCache.
SoleConformingTypeCache.insert(std::pair<ProtocolDecl *, NominalTypeDecl *>(
Protocol, SoleConformingNTD));
// Return SoleConformingNTD.
return SoleConformingNTD;
}
static bool
bothUsedInPHI(const MachineBasicBlock &A,
SmallPtrSet<MachineBasicBlock*, 8> SuccsB) {
for (MachineBasicBlock::const_succ_iterator SI = A.succ_begin(),
SE = A.succ_end(); SI != SE; ++SI) {
MachineBasicBlock *BB = *SI;
if (SuccsB.count(BB) && !BB->empty() && BB->begin()->isPHI())
return true;
}
return false;
}
/// InsertCopies - insert copies into MBB and all of its successors
void StrongPHIElimination::InsertCopies(MachineDomTreeNode* MDTN,
SmallPtrSet<MachineBasicBlock*, 16>& visited) {
MachineBasicBlock* MBB = MDTN->getBlock();
visited.insert(MBB);
std::set<unsigned> pushed;
LiveIntervals& LI = getAnalysis<LiveIntervals>();
// Rewrite register uses from Stacks
for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
I != E; ++I) {
if (I->isPHI())
continue;
for (unsigned i = 0; i < I->getNumOperands(); ++i)
if (I->getOperand(i).isReg() &&
Stacks[I->getOperand(i).getReg()].size()) {
// Remove the live range for the old vreg.
LiveInterval& OldInt = LI.getInterval(I->getOperand(i).getReg());
LiveInterval::iterator OldLR =
OldInt.FindLiveRangeContaining(LI.getInstructionIndex(I).getUseIndex());
if (OldLR != OldInt.end())
OldInt.removeRange(*OldLR, true);
// Change the register
I->getOperand(i).setReg(Stacks[I->getOperand(i).getReg()].back());
// Add a live range for the new vreg
LiveInterval& Int = LI.getInterval(I->getOperand(i).getReg());
VNInfo* FirstVN = *Int.vni_begin();
FirstVN->setHasPHIKill(false);
LiveRange LR (LI.getMBBStartIdx(I->getParent()),
LI.getInstructionIndex(I).getUseIndex().getNextSlot(),
FirstVN);
Int.addRange(LR);
}
}
// Schedule the copies for this block
ScheduleCopies(MBB, pushed);
// Recur down the dominator tree.
for (MachineDomTreeNode::iterator I = MDTN->begin(),
E = MDTN->end(); I != E; ++I)
if (!visited.count((*I)->getBlock()))
InsertCopies(*I, visited);
// As we exit this block, pop the names we pushed while processing it
for (std::set<unsigned>::iterator I = pushed.begin(),
E = pushed.end(); I != E; ++I)
Stacks[*I].pop_back();
}
/// computeDFS - Computes the DFS-in and DFS-out numbers of the dominator tree
/// of the given MachineFunction. These numbers are then used in other parts
/// of the PHI elimination process.
void StrongPHIElimination::computeDFS(MachineFunction& MF) {
SmallPtrSet<MachineDomTreeNode*, 8> frontier;
SmallPtrSet<MachineDomTreeNode*, 8> visited;
unsigned time = 0;
MachineDominatorTree& DT = getAnalysis<MachineDominatorTree>();
MachineDomTreeNode* node = DT.getRootNode();
std::vector<MachineDomTreeNode*> worklist;
worklist.push_back(node);
while (!worklist.empty()) {
MachineDomTreeNode* currNode = worklist.back();
if (!frontier.count(currNode)) {
frontier.insert(currNode);
++time;
preorder.insert(std::make_pair(currNode->getBlock(), time));
}
bool inserted = false;
for (MachineDomTreeNode::iterator I = currNode->begin(), E = currNode->end();
I != E; ++I)
if (!frontier.count(*I) && !visited.count(*I)) {
worklist.push_back(*I);
inserted = true;
break;
}
if (!inserted) {
frontier.erase(currNode);
visited.insert(currNode);
maxpreorder.insert(std::make_pair(currNode->getBlock(), time));
worklist.pop_back();
}
}
}
bool ReduceCrashingInstructions::TestInsts(std::vector<const Instruction*>
&Insts) {
// Clone the program to try hacking it apart...
ValueToValueMapTy VMap;
Module *M = CloneModule(BD.getProgram(), VMap);
// Convert list to set for fast lookup...
SmallPtrSet<Instruction*, 64> Instructions;
for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
assert(!isa<TerminatorInst>(Insts[i]));
Instructions.insert(cast<Instruction>(VMap[Insts[i]]));
}
outs() << "Checking for crash with only " << Instructions.size();
if (Instructions.size() == 1)
outs() << " instruction: ";
else
outs() << " instructions: ";
for (Module::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI)
for (Function::iterator FI = MI->begin(), FE = MI->end(); FI != FE; ++FI)
for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E;) {
Instruction *Inst = I++;
if (!Instructions.count(Inst) && !isa<TerminatorInst>(Inst) &&
!isa<LandingPadInst>(Inst)) {
if (!Inst->getType()->isVoidTy())
Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
Inst->eraseFromParent();
}
}
// Verify that this is still valid.
PassManager Passes;
Passes.add(createVerifierPass());
Passes.add(createDebugInfoVerifierPass());
Passes.run(*M);
// Try running on the hacked up program...
if (TestFn(BD, M)) {
BD.setNewProgram(M); // It crashed, keep the trimmed version...
// Make sure to use instruction pointers that point into the now-current
// module, and that they don't include any deleted blocks.
Insts.clear();
for (SmallPtrSet<Instruction*, 64>::const_iterator I = Instructions.begin(),
E = Instructions.end(); I != E; ++I)
Insts.push_back(*I);
return true;
}
delete M; // It didn't crash, try something else.
return false;
}
void LowerEmAsyncify::FindContextVariables(AsyncCallEntry & Entry) {
BasicBlock *AfterCallBlock = Entry.AfterCallBlock;
Function & F = *AfterCallBlock->getParent();
// Create a new entry block as if in the callback function
// theck check variables that no longer properly dominate their uses
BasicBlock *EntryBlock = BasicBlock::Create(TheModule->getContext(), "", &F, &F.getEntryBlock());
BranchInst::Create(AfterCallBlock, EntryBlock);
DominatorTreeWrapperPass DTW;
DTW.runOnFunction(F);
DominatorTree& DT = DTW.getDomTree();
// These blocks may be using some values defined at or before AsyncCallBlock
BasicBlockSet Ramifications = FindReachableBlocksFrom(AfterCallBlock);
SmallPtrSet<Value*, 256> ContextVariables;
Values Pending;
// Examine the instructions, find all variables that we need to store in the context
for (BasicBlockSet::iterator RI = Ramifications.begin(), RE = Ramifications.end(); RI != RE; ++RI) {
for (BasicBlock::iterator I = (*RI)->begin(), E = (*RI)->end(); I != E; ++I) {
for (unsigned i = 0, NumOperands = I->getNumOperands(); i < NumOperands; ++i) {
Value *O = I->getOperand(i);
if (Instruction *Inst = dyn_cast<Instruction>(O)) {
if (Inst == Entry.AsyncCallInst) continue; // for the original async call, we will load directly from async return value
if (ContextVariables.count(Inst) != 0) continue; // already examined
if (!DT.dominates(Inst, I->getOperandUse(i))) {
// `I` is using `Inst`, yet `Inst` does not dominate `I` if we arrive directly at AfterCallBlock
// so we need to save `Inst` in the context
ContextVariables.insert(Inst);
Pending.push_back(Inst);
}
} else if (Argument *Arg = dyn_cast<Argument>(O)) {
// count() should be as fast/slow as insert, so just insert here
ContextVariables.insert(Arg);
}
}
}
}
// restore F
EntryBlock->eraseFromParent();
Entry.ContextVariables.clear();
Entry.ContextVariables.reserve(ContextVariables.size());
for (SmallPtrSet<Value*, 256>::iterator I = ContextVariables.begin(), E = ContextVariables.end(); I != E; ++I) {
Entry.ContextVariables.push_back(*I);
}
}
/// Record ICmp conditions relevant to any argument in CS following Pred's
/// single successors. If there are conflicting conditions along a path, like
/// x == 1 and x == 0, the first condition will be used.
static void recordConditions(CallSite CS, BasicBlock *Pred,
ConditionsTy &Conditions) {
recordCondition(CS, Pred, CS.getInstruction()->getParent(), Conditions);
BasicBlock *From = Pred;
BasicBlock *To = Pred;
SmallPtrSet<BasicBlock *, 4> Visited;
while (!Visited.count(From->getSinglePredecessor()) &&
(From = From->getSinglePredecessor())) {
recordCondition(CS, From, To, Conditions);
Visited.insert(From);
To = From;
}
}
bool LoopSafetyInfo::allLoopPathsLeadToBlock(const Loop *CurLoop,
const BasicBlock *BB,
const DominatorTree *DT) const {
assert(CurLoop->contains(BB) && "Should only be called for loop blocks!");
// Fast path: header is always reached once the loop is entered.
if (BB == CurLoop->getHeader())
return true;
// Collect all transitive predecessors of BB in the same loop. This set will
// be a subset of the blocks within the loop.
SmallPtrSet<const BasicBlock *, 4> Predecessors;
collectTransitivePredecessors(CurLoop, BB, Predecessors);
// Make sure that all successors of all predecessors of BB are either:
// 1) BB,
// 2) Also predecessors of BB,
// 3) Exit blocks which are not taken on 1st iteration.
// Memoize blocks we've already checked.
SmallPtrSet<const BasicBlock *, 4> CheckedSuccessors;
for (auto *Pred : Predecessors) {
// Predecessor block may throw, so it has a side exit.
if (blockMayThrow(Pred))
return false;
for (auto *Succ : successors(Pred))
if (CheckedSuccessors.insert(Succ).second &&
Succ != BB && !Predecessors.count(Succ))
// By discharging conditions that are not executed on the 1st iteration,
// we guarantee that *at least* on the first iteration all paths from
// header that *may* execute will lead us to the block of interest. So
// that if we had virtually peeled one iteration away, in this peeled
// iteration the set of predecessors would contain only paths from
// header to BB without any exiting edges that may execute.
//
// TODO: We only do it for exiting edges currently. We could use the
// same function to skip some of the edges within the loop if we know
// that they will not be taken on the 1st iteration.
//
// TODO: If we somehow know the number of iterations in loop, the same
// check may be done for any arbitrary N-th iteration as long as N is
// not greater than minimum number of iterations in this loop.
if (CurLoop->contains(Succ) ||
!CanProveNotTakenFirstIteration(Succ, DT, CurLoop))
return false;
}
// All predecessors can only lead us to BB.
return true;
}
bool ReduceCrashingNamedMDOps::TestNamedMDOps(
std::vector<const MDNode *> &NamedMDOps) {
// Convert list to set for fast lookup...
SmallPtrSet<const MDNode *, 32> OldMDNodeOps;
for (unsigned i = 0, e = NamedMDOps.size(); i != e; ++i) {
OldMDNodeOps.insert(NamedMDOps[i]);
}
outs() << "Checking for crash with only " << OldMDNodeOps.size();
if (OldMDNodeOps.size() == 1)
outs() << " named metadata operand: ";
else
outs() << " named metadata operands: ";
ValueToValueMapTy VMap;
Module *M = CloneModule(BD.getProgram(), VMap).release();
// This is a little wasteful. In the future it might be good if we could have
// these dropped during cloning.
for (auto &NamedMD : BD.getProgram()->named_metadata()) {
// Drop the old one and create a new one
M->eraseNamedMetadata(M->getNamedMetadata(NamedMD.getName()));
NamedMDNode *NewNamedMDNode =
M->getOrInsertNamedMetadata(NamedMD.getName());
for (MDNode *op : NamedMD.operands())
if (OldMDNodeOps.count(op))
NewNamedMDNode->addOperand(cast<MDNode>(MapMetadata(op, VMap)));
}
// Verify that this is still valid.
legacy::PassManager Passes;
Passes.add(createVerifierPass(/*FatalErrors=*/false));
Passes.run(*M);
// Try running on the hacked up program...
if (TestFn(BD, M)) {
// Make sure to use instruction pointers that point into the now-current
// module, and that they don't include any deleted blocks.
NamedMDOps.clear();
for (const MDNode *Node : OldMDNodeOps)
NamedMDOps.push_back(cast<MDNode>(*VMap.getMappedMD(Node)));
BD.setNewProgram(M); // It crashed, keep the trimmed version...
return true;
}
delete M; // It didn't crash, try something else.
return false;
}
static SmallPtrSet<BasicBlock *, 4> getCoroBeginPredBlocks(CoroBeginInst *CB) {
// Collect all blocks that we need to look for instructions to relocate.
SmallPtrSet<BasicBlock *, 4> RelocBlocks;
SmallVector<BasicBlock *, 4> Work;
Work.push_back(CB->getParent());
do {
BasicBlock *Current = Work.pop_back_val();
for (BasicBlock *BB : predecessors(Current))
if (RelocBlocks.count(BB) == 0) {
RelocBlocks.insert(BB);
Work.push_back(BB);
}
} while (!Work.empty());
return RelocBlocks;
}
void AssumptionCacheTracker::verifyAnalysis() const {
#ifndef NDEBUG
SmallPtrSet<const CallInst *, 4> AssumptionSet;
for (const auto &I : AssumptionCaches) {
for (auto &VH : I.second->assumptions())
if (VH)
AssumptionSet.insert(cast<CallInst>(VH));
for (const BasicBlock &B : cast<Function>(*I.first))
for (const Instruction &II : B)
if (match(&II, m_Intrinsic<Intrinsic::assume>()))
assert(AssumptionSet.count(cast<CallInst>(&II)) &&
"Assumption in scanned function not in cache");
}
#endif
}
bool ADCE::runOnFunction(Function& F) {
if (skipOptnoneFunction(F))
return false;
SmallPtrSet<Instruction*, 128> alive;
SmallVector<Instruction*, 128> worklist;
// Collect the set of "root" instructions that are known live.
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
if (isa<TerminatorInst>(I.getInstructionIterator()) ||
isa<DbgInfoIntrinsic>(I.getInstructionIterator()) ||
isa<LandingPadInst>(I.getInstructionIterator()) ||
I->mayHaveSideEffects()) {
alive.insert(I.getInstructionIterator());
worklist.push_back(I.getInstructionIterator());
}
// Propagate liveness backwards to operands.
while (!worklist.empty()) {
Instruction* curr = worklist.pop_back_val();
for (Instruction::op_iterator OI = curr->op_begin(), OE = curr->op_end();
OI != OE; ++OI)
if (Instruction* Inst = dyn_cast<Instruction>(OI))
if (alive.insert(Inst))
worklist.push_back(Inst);
}
// The inverse of the live set is the dead set. These are those instructions
// which have no side effects and do not influence the control flow or return
// value of the function, and may therefore be deleted safely.
// NOTE: We reuse the worklist vector here for memory efficiency.
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
if (!alive.count(I.getInstructionIterator())) {
worklist.push_back(I.getInstructionIterator());
I->dropAllReferences();
}
for (SmallVectorImpl<Instruction *>::iterator I = worklist.begin(),
E = worklist.end(); I != E; ++I) {
++NumRemoved;
(*I)->eraseFromParent();
}
return !worklist.empty();
}
/// Find an insertion point that dominates all uses.
SmallPtrSet<Instruction *, 8> ConstantHoistingPass::findConstantInsertionPoint(
const ConstantInfo &ConstInfo) const {
assert(!ConstInfo.RebasedConstants.empty() && "Invalid constant info entry.");
// Collect all basic blocks.
SmallPtrSet<BasicBlock *, 8> BBs;
SmallPtrSet<Instruction *, 8> InsertPts;
for (auto const &RCI : ConstInfo.RebasedConstants)
for (auto const &U : RCI.Uses)
BBs.insert(findMatInsertPt(U.Inst, U.OpndIdx)->getParent());
if (BBs.count(Entry)) {
InsertPts.insert(&Entry->front());
return InsertPts;
}
if (BFI) {
findBestInsertionSet(*DT, *BFI, Entry, BBs);
for (auto BB : BBs) {
BasicBlock::iterator InsertPt = BB->begin();
for (; isa<PHINode>(InsertPt) || InsertPt->isEHPad(); ++InsertPt)
;
InsertPts.insert(&*InsertPt);
}
return InsertPts;
}
while (BBs.size() >= 2) {
BasicBlock *BB, *BB1, *BB2;
BB1 = *BBs.begin();
BB2 = *std::next(BBs.begin());
BB = DT->findNearestCommonDominator(BB1, BB2);
if (BB == Entry) {
InsertPts.insert(&Entry->front());
return InsertPts;
}
BBs.erase(BB1);
BBs.erase(BB2);
BBs.insert(BB);
}
assert((BBs.size() == 1) && "Expected only one element.");
Instruction &FirstInst = (*BBs.begin())->front();
InsertPts.insert(findMatInsertPt(&FirstInst));
return InsertPts;
}
bool ADCE::runOnFunction(Function& F) {
if (skipOptnoneFunction(F))
return false;
SmallPtrSet<Instruction*, 128> Alive;
SmallVector<Instruction*, 128> Worklist;
// Collect the set of "root" instructions that are known live.
for (Instruction &I : instructions(F)) {
if (isa<TerminatorInst>(I) || isa<DbgInfoIntrinsic>(I) || I.isEHPad() ||
I.mayHaveSideEffects()) {
Alive.insert(&I);
Worklist.push_back(&I);
}
}
// Propagate liveness backwards to operands.
while (!Worklist.empty()) {
Instruction *Curr = Worklist.pop_back_val();
for (Use &OI : Curr->operands()) {
if (Instruction *Inst = dyn_cast<Instruction>(OI))
if (Alive.insert(Inst).second)
Worklist.push_back(Inst);
}
}
// The inverse of the live set is the dead set. These are those instructions
// which have no side effects and do not influence the control flow or return
// value of the function, and may therefore be deleted safely.
// NOTE: We reuse the Worklist vector here for memory efficiency.
for (Instruction &I : instructions(F)) {
if (!Alive.count(&I)) {
Worklist.push_back(&I);
I.dropAllReferences();
}
}
for (Instruction *&I : Worklist) {
++NumRemoved;
I->eraseFromParent();
}
return !Worklist.empty();
}
/// FindFunctionBackedges - Analyze the specified function to find all of the
/// loop backedges in the function and return them. This is a relatively cheap
/// (compared to computing dominators and loop info) analysis.
///
/// The output is added to Result, as pairs of <from,to> edge info.
void llvm::FindFunctionBackedges(const Function &F,
SmallVectorImpl<std::pair<const BasicBlock*,const BasicBlock*> > &Result) {
const BasicBlock *BB = &F.getEntryBlock();
if (succ_begin(BB) == succ_end(BB))
return;
SmallPtrSet<const BasicBlock*, 8> Visited;
SmallVector<std::pair<const BasicBlock*, succ_const_iterator>, 8> VisitStack;
SmallPtrSet<const BasicBlock*, 8> InStack;
Visited.insert(BB);
VisitStack.push_back(std::make_pair(BB, succ_begin(BB)));
InStack.insert(BB);
do {
std::pair<const BasicBlock*, succ_const_iterator> &Top = VisitStack.back();
const BasicBlock *ParentBB = Top.first;
succ_const_iterator &I = Top.second;
bool FoundNew = false;
while (I != succ_end(ParentBB)) {
BB = *I++;
if (Visited.insert(BB)) {
FoundNew = true;
break;
}
// Successor is in VisitStack, it's a back edge.
if (InStack.count(BB))
Result.push_back(std::make_pair(ParentBB, BB));
}
if (FoundNew) {
// Go down one level if there is a unvisited successor.
InStack.insert(BB);
VisitStack.push_back(std::make_pair(BB, succ_begin(BB)));
} else {
// Go up one level.
InStack.erase(VisitStack.pop_back_val().first);
}
} while (!VisitStack.empty());
}
// FindCopyInsertPoint - Find a safe place in MBB to insert a copy from SrcReg
// when following the CFG edge to SuccMBB. This needs to be after any def of
// SrcReg, but before any subsequent point where control flow might jump out of
// the basic block.
MachineBasicBlock::iterator
llvm::PHIElimination::FindCopyInsertPoint(MachineBasicBlock &MBB,
MachineBasicBlock &SuccMBB,
unsigned SrcReg) {
// Handle the trivial case trivially.
if (MBB.empty())
return MBB.begin();
// Usually, we just want to insert the copy before the first terminator
// instruction. However, for the edge going to a landing pad, we must insert
// the copy before the call/invoke instruction.
if (!SuccMBB.isLandingPad())
return MBB.getFirstTerminator();
// Discover any defs/uses in this basic block.
SmallPtrSet<MachineInstr*, 8> DefUsesInMBB;
for (MachineRegisterInfo::reg_iterator RI = MRI->reg_begin(SrcReg),
RE = MRI->reg_end(); RI != RE; ++RI) {
MachineInstr *DefUseMI = &*RI;
if (DefUseMI->getParent() == &MBB)
DefUsesInMBB.insert(DefUseMI);
}
MachineBasicBlock::iterator InsertPoint;
if (DefUsesInMBB.empty()) {
// No defs. Insert the copy at the start of the basic block.
InsertPoint = MBB.begin();
} else if (DefUsesInMBB.size() == 1) {
// Insert the copy immediately after the def/use.
InsertPoint = *DefUsesInMBB.begin();
++InsertPoint;
} else {
// Insert the copy immediately after the last def/use.
InsertPoint = MBB.end();
while (!DefUsesInMBB.count(&*--InsertPoint)) {}
++InsertPoint;
}
// Make sure the copy goes after any phi nodes however.
return SkipPHIsAndLabels(MBB, InsertPoint);
}
